Improving the Properties of SrRuO3 Electrode Films Grown by Atomic Layer-Deposited SrO and Pulsed Chemical Vapor-Deposited RuO2 Using Al2O3 Capping Layers

Abstract

Inthis study, an Al2O3 capping layer (ACL)was utilized to enhance the surface morphology and electrical propertiesof SrRuO3 (SRO) electrode films deposited via combinedatomic layer deposition and pulsed chemical vapor deposition. To crystallizethe SRO films, postdeposition annealing (PDA) was necessary; however,this led to material agglomeration and degradation of the surfacemorphology. Therefore, to address this issue, the ACL was used toreduce agglomeration by inhibiting material migration. Next, the appropriatethickness of ACL and PDA conditions, which ensured high crystallinityand suppressed agglomeration, were investigated. Subsequently, theACL was wet-etched using an aqueous HF solution. The changes in thelayer density of Ru and Sr were analyzed, and the stoichiometric SROfilm was stably obtained after PDA and wet-etching. The resultingACL-etched SRO film had an improved surface morphology, lower resistivity(& SIM;800 & mu;& omega;& BULL;cm), and lower root-mean-squaredroughness (1.15 nm) compared to uncapped SRO films at a thicknessof 25 nm. Finally, the atomic layer-deposited SrTiO3 dielectriclayer on the SRO film was in situ-crystallized, with a high dielectricconstant of 81 and a minimal interfacial equivalent oxide thicknessof 0.03 nm.